Spas with reservation required

Längenfeld, Tyrol

A large thermal bath and 4-star hotel spa in the Ötztal valley near Längenfeld, with indoor-outdoor pools, a sauna garden and a dedicated kids' water world.

Hudson, New York

Adults-only communal thermal baths and steam room in downtown Hudson, NY, with day passes, memberships and treatment-plus-soak packages.

Budapest

A centuries-old Turkish-style thermal bath on the Buda riverside with pools, saunas, massages and weekend late-night soaking hours.